Water purification systems that take advantage of the germicidal properties of ozone enjoy a variety of uses, including the purification of effluent from industrial processes and portable facilities, such as are found on boats, as well as the sterilization of circulating water in hot tubs and swimming pools. Such systems typically comprise an ozone-producing apparatus and an ozone/water reactor, or contactor. The ozone-producing apparatus typically comprises an air chamber, within which an ultraviolet ("UV") lamp is positioned. An air stream flows past the UV lamp, with the lamp's radiation converting a portion of the oxygen in the air to ozone. The ozonated air is then channelled to the contactor for reaction with the contaminated water. The spent ozonated air may be collected for recirculation within the system.
The contactor is faced with several requirements and limitations. The essential requirement of a contactor is that it thoroughly combine the ozonated air with the contaminated fluid. Various means have been proposed to achieve this. For example, U.S. Pat. No. 2,009,230 (Hartman) discloses a long helical tube with ozonated air and contaminated water being introduced into one end, and the other end discharging into a secondary reaction chamber. Other devices have utilized a reaction chamber within which the ozonated air and the fluid are stirred, as in U.S. Pat. No. 4,728,441 (King), or wherein the reaction chamber simply comprises a tank into which the ozone and contaminated fluid are introduced at one end and removed from the other end, for example as disclosed in U.S. Pat. No. 4,256,574 (Bhargava). In general, a more complete reaction of the ozone and fluid is possible where the reaction chamber is elongate, such as a long tube, with the reactants being introduced at one end and withdrawn from the other end on a continuous basis. In contrast, a reaction chamber comprising a tank is better suited to batch processing of reactants; this approach is not in general well suited to the requirements of an ozone contactor.
Where the reaction chamber consists of a long tubular chamber, which may total 18 feet or more in length, the tube should preferably be coiled or otherwise configured to be relatively compact.
In order to thoroughly combine the ozone and contaminated fluid, it is not sufficient to merely bubble the ozone through the fluid. There must be provided additional means to thoroughly combine the water and ozonated air. The use of a stirring paddle, as disclosed in King, is applicable for use with a relatively large reaction chamber, but not in a compact tube-type contactor. Accordingly, it is desirable to provide means to thoroughly combine the reactants within a tubular reaction chamber. This may be accomplished by providing means to finely divide the ozonated gas as it flows through the chamber, for example by passing it through a fine mesh or a bed of granular material.